At the Southwest Foundation for Research and Education a detailed analysis of host-herpesvirus interaction in nonhuman primates will be made. Previous studies have demonstrated that the baboon is relatively immunologically competent by human standards, the cebus monkey is of intermediate competence while the marmoset is markedly deficient in a number of parameters of thymic and bursal dependent systems. Sophisticated tests of immunological competence will be carried out to find the factors in each of the three species which are most critical to defense against infectious and oncogenic agents. In these primates, two herpesviruses will be intensively studied. H. saimiri causes fatal lymphoma in marmosets, may cause the same disease in cebus monkeys, and induces no clinical disease in baboons. H. hominis, type 2, induces a fatal disseminated infection after local inoculation in marmosets, produces a recurrent mild disease after such inoculation in cebus monkeys and causes no observable disease in baboons. Animals of each species will be sensitized with inactivated viruses as well as replicating live forms of each of the two herpesviruses. The animals' clinical response to systemic and local inoculation, correlated with many tests of bursal immune, thymic immune and nonspecific defense functions should provide a unique opportunity to recognize primate host factors that are most critical in defense against herpesviruses. Based on the preceding information, immunotherapeutic approaches will be attempted to augment those host factors felt to be most critical. Herpes sensitized baboons will provide hyperimmune antisera and immunocompetent lymphocytes for preparation of immunotherapeutic reagents to be given actively, passively or adoptively to marmosets and cebus monkeys at risk. It is anticipated that predictable and efficacious immunotherapeutic methods will be recognized which can be effectively applied to the human primate, man.